Gatherings of walruses crowded together on northwestern Alaska shorelines, like the congregation of about 35,000 animals spotted this weekend near the village of Point Lay, have become regular occurrences in the new era of scarce summer sea ice. (Alaska Dispatch News)
Thanks to our once-and-future oceans expert, Julie, for the heads-up and help on this current event connection!
- More than 35,000 walruses are crowding on a single beach near Point Lay, Alaska. Why is dangerous for walruses to gather in such large numbers?
- Stampedes. Walruses are huge marine mammals, regularly weighing more than 1,000 kilograms (1,800 pounds). Although they are remarkably agile in water, adult walruses can trample juveniles—and each other—when moving around on the land. In fact, authorities are so worried about a walrus stampede they’ve actually re-routed flights to avoid the area around Point Lay! Read more about local and national responses to the walruses in this typically terrific article from the Guardian.
- Tusks. Both male and female walruses have long teeth (their canines) called tusks. Tusks can grow to 100 centimeters (39 inches) on a male walrus. Walruses are territorial and sometimes use their tusks to defend their territory.
- Predators. Walruses spend most of their lives at sea, where their only real predator is the orca (killer whale). Such a large, beach-bound herd can be easy prey for terrestrial predators such as bears. Biologists have already spotted dozens of walrus carcasses on the beach—and evidence of both brown bears and polar bears in the area.
- Shrinking sea ice has meant walruses at Point Lay have to travel 240 kilometers (150 miles) to their feeding grounds, a shallow region known as the Hanna Shoal. (Take a look at this MapMaker Interactive map to see the migration the walruses must take.) Why do biologists say it is a problem for walruses to travel so far to feed?
- It takes the walruses about two weeks of non-stop swimming to reach (and return from) the Hanna Shoal. (Read more about the vibrant Arctic ecosystem at the Hanna Shoal here.) They burn so many calories traveling to and from the Hanna Shoal, they may not be able to pack on the pounds of blubber they need as insulation from the frigid waters of the Arctic winter.
- Have students explore more on energy transfer and loss in this food web activity.
- Climate change has led to melting sea ice. Walruses need this critical habitat in order to survive. What other marine mammals rely on the Arctic sea ice for survival?
- Polar bears are the emblematic figure of global warming. They depend on sea ice to reach their prey—mostly ringed and bearded seals. Take a look at the polar bear’s shrinking territory on this map.
- Seals, including harp seals like this little guy, use sea ice as floating platforms for nursing, resting, and eating. Prey for juvenile seals (such as crustaceans) is also typically found on the edge of sea ice.
- Seabirds such as thick-billed murres depend on sea ice to support their primary sources of food, including schools of cod and audiences of squid. (Yes, that’s one of the quasi-correct terms for a group of squid. Another is a squad—a squad of squid. Say that five times fast. Most scientists seem to prefer a “shoal of squid,” although that isn’t as much fun.)
- Explore other organisms that live in the Arctic in this coloring page.
Alaska Dispatch News article: Huge onshore crowds of walruses a new phenomenon for Arctic Alaska, scientists say
MapMaker Interactive: Northern Alaska, with Point Lay and the Hanna Shoal
Activity: Marine Food Webs
Coloring Page: Arctic Ecosystem